Comparison of clinical and cognitive outcomes of bilateral and right unilateral ECT in community settings

Abstract

The purpose of this study was to compare the clinical and cognitive effects of bilateral and unilateral electroconvulsive therapy as it is practiced in the community. A total of 185 patients from eight community hospitals that use either bilateral or unilateral ECT took part in the study. All patients were in a major depressive episode. The patients were administered a battery of clinical and neuropsychological measures before, just after, and 6 months after a course of ECT. The main clinical outcomes measures were the Hamilton Rating Scale for Depression and the Beck Depression Inventory-II. Global cognitive status was measured using the 30-item Mini-mental Status Examination, verbal memory was assessed using the Buschke Selective Reminding Test, visual memory was assessed using the Complex Figure Test, and autobiographical memory was assessed using the Autobiographical Memory Interview. In addition patients were administered four computerized measures of reaction time and attention, simple reaction time, choice reaction time, the Continuous Performance Test, and the Stroop Color-Word Test. All of the patients' ECT treatments were observed and detailed recordings were made of the main treatment variables. ^ The results showed that depressive symptoms were significantly improved after a course of ECT. There was no difference between bilateral and unilateral ECT on measures of depression severity at the post-ECT assessment point. Patients who received bilateral ECT performed worse on the autobiographical memory measure and the two measures of attention after ECT than patients who received unilateral ECT. In addition patients who received bilateral ECT tended to perform worse on the global cognitive status measure and the measure of delayed verbal recall. There were no differences between the groups on either reaction time measure or measures of immediate verbal and delayed visual memory. After six months patients who received bilateral ECT continued to have a deficit relative to patients who received unilateral treatment on the measure of autobiographical memory. It should be noted that the effect sizes for the differences in cognitive function between bilateral and unilateral ECT were small, however given there was no difference in clinical efficacy between the two electrode placements any difference in cognitive efficacy must be considered important. ^